Triple electron gun assembly having units attached by glass beads to protrusion from convergence electrode

ABSTRACT

A triple electron gun assembly comprising three stacks of electrodes so arranged as to have their axes slightly inclined for convergence and a cup-shaped convergence electrode secured to the forward ends of the three electron gun units, said cup-shaped convergence electrode being provided with a protrusion having cylindrical walls corresponding in size and shape to the forward ends of the three electron gun units.

O Umted States Patent 1 1 Sawagata [4 1 Apr. 3, 1973 [54] TRIPLEELECTRON GUN ASSEMBLY [56] References Cited HAVING UNITS ATTACHED BYGLASS BEADS TO PROTRUSION FROM UNITED STATES PATENTS v CONVERGENCEELECTRODE 3,250,935 5/1966 Johnson ..313/69 c x e 3 603 829 9/1971Tsuneta et al. [7 5] lnventor. Shmlchl Sawagata, Nerlma-ku,

Tokyo Japan 3,643,121 2/1972 Sawagata et a1. ..3l3/70 C [73] Assignee:Tokyo Shibaura Electric Co., Ltd., primary Examine,- Robert Sega]Kawasakishi1 Japan Attorney-Flynn & Frishauf [22] Filed: Sept. 29, 1971i R C 57 ABST A T [21] Appl. No.: 184,776 l A triple electron gunassembly comprising three stacks of electrodes so arranged as to havetheir axes slightly [30] Foreign Apphcamm Pnonty Data inclined forconvergence and a cup-shaped conver- Oct. 20, 1970 Japan ..45/l03549gence electrode secured to the forward ends of the three electron gununits, said cup-shaped convergence U-S- CL C, electrode being provided aprotrusion having 3.13/262 cylindrical walls corresponding in size andshape to [51] Int. Cl. ..H0l 29/02, H01 29/50 the f d ends f the threeelectron gun units [58] Field 0i Search ..3l3/70 C, 69 C, 92 B 5 Claims,4 Drawing Figures TRIPLE ELECTRON GUN ASSEMBLY HAVING UNITS ATTACHED BYGLASS BEADS TO PROTRUSION FROM CONVERGENCE ELECTRODE BACKGROUND OF THEINVENTION This invention relates to a triple gun assembly. With theprior art triple electron gun assembly, the convergence electrode isformed into a cup-shape whose bottom is provided with locating stripsand three apertures whose centers are positioned at the apices of anequilateral triangle. To the bottom of said convergence electrode areglass fused three assembled electron gun members with the forward endsdefined in position by said locating strips. Said assembly consists ofthree electron gun units prepared from stacks of electrodes andintegrally fixed at the prescribed convergence angle. With suchconventional electron gun assembly, there are required complicatedassembling jigs to secure the convergence electrode to the threecombined electron gun members in coaxial relationship and with highprecision. Moreover, the assembling operation is accompanied withconsiderable difficulties, most likely causing the assembled electrongun members to be undesirably ill matched or damaged with the resultantoccurrence of many disqualified products.

SUMMARY OF THE INVENTION It is accordingly the object of this inventionto improve the construction of the convergence electrode and threeelectron gun members being assembled, thereby providing a tripleelectron gun assembly which can be integrally set up with high precisionby a simple assembling operation.

In a triple electron gun assembly according to this invention, theconvergence electrode is provided at the bottom with a protrusion, towhich there are fitted the forward ends of the three combined electrongun members. The protrusion corresponds in size and shape with the topends of the three electron gun units constituting the three combinedelectron gun members. On the edge of the protrusion are preferablyformed three tongue members at an equal interval. The forward ends ofthe three electron gun units are also preferably provided with tonguemembers corresponding to those of the protrusion. The convergenceelectrode is fixed to the forward ends of the three assembled electrongun members by welding the tongue members of the protrusion of theconvergence electrode with those of the gun members.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of thetriple electron gun assembly of this invention;

FIG. 2 is a perspective view of the convergence electrode ofFIG. 1;

FIG. 3 is a perspective view of a shield member fitted to theconvergence electrode of FIG. 2; and

FIG. 4 is a perspective view of the three assembled electron gun membersof FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a tripleelectron gun assembly prepared by fitting to a convergence electrode 1 1three electron gun members 30 consisting of three electron gun units 36integrally put together. The convergence electrode 11 is formed into acup-shape, and has its peripheral wall bored with three pairs of slits12, each pair being disposed at an equal interval. Into each slit 12 isinserted a substantially L-shaped magnetic strip 13. The cup-shapedconvergence electrode 11 has a protrusion 14 formed at the bottom incoaxial relationship. The protrusion 14 has three cylindrical walls 15the axial centers of which are positioned respectively on the apices ofan equilateral triangle. The protrusion 14 further has three throughholes 16 bored coaxially with the cylindrical walls 15 and tonguemembers 17 extending outward preferably from those parts of theperipheral edge of the bottom surface 15 of the protrusion 14 which facethe through holes 16 as viewed from the center of the protrusion 14. Theconcave portions defined by the adjacent cylindrical walls 15 have aplain surface 19, from the center of which there are cut out twomutually facing upright pieces to constitute a pair of support members20. In that portion of the bottom of the convergence electrode 11 whichfaces the interspace between said support members 20 is formed a notch21. In that portion of the peripheral edge of the forward end of theconvergence electrode 11 which is disposed opposite to said notch 21 isformed a notch 22. Into the convergence electrode 11 of the aforesaidconstruction is inserted a shield electrode 25 illustrated in FIG. 3consisting of three shield plates 26, which define an equal interiorangle between the adjacent ones, that is, are formed in a generallyY-shape. Each shield plate 26 is formed at one end into a steppedportion, in one side of which there is cut out a notch 27. -At the outercorner of the opposite end of said shield plate 26 is integrallyprovided a protrusion 28 at right angles to the plane of said plate 26.

Referring to FIG. 4, a triple electron gun assembly 30 is formed ofthree electron gun units 36 integrally put together by glass beads 37 ata prescribed slight convergence angle to each other, each of said units36 comprising a first cylindrical grid electrode 31 containing a cathode(not shown) and second, third, fourth and fifth cylindrical gridelectrodes 32, 33, 34 and 35 arranged coaxially with said first gridelectrode 31. The outer ends of the fifth grid electrodes 35 areprovided with tongue members 38 corresponding to those of theaforementioned convergence electrode 11. This triple electron gunassembly 30 is fitted to the bottom 18 of the protrusion 14 of theconvergence electrode 11, in such a manner that the outer ends of thefifth grid electrodes 35 are brought into contact with said bottom 18with the tongue members 17 of the protrusion 14 superposed on the tonguemembers 38 of said fifth electrodes 35. Both groups 17 and 38 of thetongue members are welded together so as to secure the triple electrongun assembly 30 to the convergence electrode 11. The top ends of theglass beads 37 are fused jointly to fix the forward ends of the shieldplates 26 disposed in the interspaces of the three pairs of the supportmem-' bers 20 formed on the plain surfaces 19 of the concave portions ofthe protrusion 14.

There will now be described the assembling operation of the threeelectron gun units. The cup-shaped convergence electrode 11 shown inFIG. 2 is press molded in advance. Into said convergence electrode 11 isinserted a shield electrode 25 illustrated in FIG. 3.

One end of the stepped portion of each shield plate 26 of the shieldelectrode 25 is inserted between the paired support members of theconvergence electrode 11. The protrusion 28 at the outer corner of theforward end of the shield plate 26 engages the notch 22 formed in theperipheral edge of the forward end of the convergence electrode 11. Theconvergence electrode 11 into which the shield electrode 25 has beeninserted is supported by an assembling jig having three rods with saidrods inserted into the through holes 16 bored in the protrusion 14 ofthe convergence electrode 11. Each rod of the assembling jig is made topass through the fifth, fourth, third, second and first grid electrodesin turn with a spacer interposed therebetween. Between the adjacentstacks of electrodes into which the rods of the assembling jig have beeninserted are provided glass beads 37, which integrally fix the electrodestacks by being fused to the outer ends of mounting brackets 39 attachedto the respective grid electrodes 31 to 35. At this time the glass beadsare also fused to the support strips 20 formed on the plain surfaces 19of the protrusion 14' to support the convergence electrode 11 and partof the rear end of each shield plate 26 as well as to said mountingbrackets 39. After the assembling jig is removed, there is inserted amagnetic strip 13 into each of the three pairs of slits 12 formed in theperipheral walls of the convergence electrode 11, and there is receiveda cathode in the first grid electrode, thus completing a triple electrongun assembly.

What is claimed is:

1. A triple electron gun assembly comprising:

three electron gun units, each including a plurality of coaxiallyarranged grid electrodes, the central axes of said gun units beingarranged to form the apices of an equilateral triangle;

glass beads provided between the adjacent electron gun units so as tointegrally fix said electron gun units together;

a cupshaped convergence electrode having a protrusion at the bottomthereof which has a surface mating with the top end of the threeelectron gun units and locating the three electron gun units so as toprovide convergent electron beams, said protrusion having threeapertures therein located along the central axes of respective ones ofthe electron gun units for passing the electron beams from saidrespective electron gun. units, said protrusion including threesubstantially cylindrical walls corresponding substantially to theoutline of the mating surfaces of said three electron gun units andthree substantially flat surfaces formed in the three concave portionsdefined by the adjacent walls of said cylindrical walls, said glassbeads being attached to the respective substantially flat surfaces, thelower surface of said protrusion being fitted to the top mating ends ofthe electron gun units so as to facilitate accurate positioning andattaching of said electron gun units to said convergence electrode.

2. The triple electron gun assembly according to claim 1 wherein uprightsupport strips are formed in said substantially flat surfaces.

3. The triple electron gun assembly according to claim 1 wherein thecylindrical walls have tongue members formed on the peripheral edge; theelectron gun units have tongue members formed at the forward ends incorresponding relationship to those of the cylindrical walls; and theprotrusion and electron gun units are so arranged that respective tonguemembers of the former are superposed on those of the latter, both groupsof tongue members being welded together to secure said electron gununits to said cupshaped convergence electrode.

4. The triple electron gun assembly according to claim 2 wherein saidgrid electrodes have mounting brackets, and the glass beads are fused tothe support strips of the convergence electrode and to said mountingbrackets of said grid electrodes so as to jointly support them.

5. The triple electron gun assembly according to claim 2 wherein saidthree substantially flat surfaces have cut-out portions, the remainingportion of each of said substantially flat surfaces defining saidupright support strips.

1. A triple electron gun assembly comprising: three electron gun units,each including a plurality of coaxially arranged grid electrodes, thecentral axes of said gun units being arranged to form the apices of anequilateral triangle; glass beads provided between the adjacent electrongun units so as to integrally fix said electron gun units together; acupshaped convergence electrode having a protrusion at the bottomthereof which has a surface mating with the top end of the threeelectron gun units and locating the three electron gun units so as toprovide convergent electron beams, said protrusion having threeapertures therein located along the central axes of respective ones ofthe electron gun units for passing the electron beams from saidrespective electron gun units, said protrusion including threesubstantially cylindrical walls corresponding substantially to theoutline of the mating surfaces of said three electron gun units andthree substantially flat surfaces formed in the three concave portionsdefined by the adjacent walls of said cylindrical walls, said glassbeads being attached to the respective substantially flat surfaces, thelower surface of said protrusion being fitted to the top mating ends ofthe electron gun units so as to facilitate accurate positioning andattaching of said electron gun units to said convergence electrode. 2.The triple electron gun assembly according to claim 1 wherein uprightsupport strips are formed in said substantially flat surfaces.
 3. Thetriple electron gun assembly according to claim 1 wherein thecylindrical walls have tongue members formed on the peripheral edge; theelectron gun units have tongue members formed at the forward ends incorresponding relationship to those of the cylindrical walls; and theprotrusion and electron gun units are so arranged that respective tonguemembers of the former are superposed on those of the latter, both groupsof tongue members being welded together to secure said electron gununits to said cupshaped convergence electrode.
 4. The triple electrongun assembly according to claim 2 wherein said grid electrodes havemounting brackets, and the glass beads are fused to the support stripsof the convergence electrode and to said mounting brackets of said gridelectrodes so as to jointly support them.
 5. The triple electron gunassembly according to claim 2 wherein said three substantially flatsurfaces have cut-out portions, the remaining portion of each of saidsubstantially flat surfaces defining said upright support strips.